Should exiting employees be: - Banned from interviewing panels? or Required by design?

The more I think about it, an exiting employee carries the deepest signal, the deepest learning and possibly the deepest bias. I mean think about it.. Isn't an exiting employee - post-loyalty, post-politics, post-pretending. So when you put them on an interview panel for their own replacement, one of two things happens: Scenario A: I don't give a fuck, hire whoever you want, I am just going to nod in Scenario B: I have super strong ethics and character, so I will hire only the best Scenario C: This talent is great - but why even work here - this place is so shitty - I should save this life at least .... could be more situations.. but you get the drift..

What's your take?